'75 Corvette "jumps" when putting it in reverse or drive?

[Curious]

I have a 1975 corvette that runs really well, but when i put it in reverse or drive, it kind of jumps or drops. Like the back end of the car will drop down, you can feel it. Not sure how to better explain it.

Someone told me the idle was set too high. Any ideas if that is right or if its something more serious or ??
Thanks to both of you, glad to hear 2 others say its the idle. I'll take it and get it adjusted.

 

[HandyManiac]

yeah there is a little adjusting screw on the side of the carb which your throttle is hooked up just back that screw up a little to releive tension on the spring

 

[Harley guy]

When you put it in gear and the car jumps , your idle is to high. Turn the idle down.